1. Field of the Invention
The present invention relates to a component having at micromechanical microphone pattern, which is implemented in a layer construction on a semiconductor substrate. The microphone pattern includes an acoustically active diaphragm which spans at least partially a sound opening nozzle on the backside of the substrate. The diaphragm is equipped with at least one movable electrode of a microphone capacitor system. Furthermore, the microphone pattern includes a stationary acoustically penetrable counterelement having through holes, which is situated in the layer construction over the diaphragm, and functions as a carrier for at least one immovable electrode of the microphone capacitor system. The diaphragm's being acted upon by sound takes place via the sound opening in the substrate and/or via the through holes in the counterelement. The diaphragm deflections resulting from this are recorded as capacitive fluctuations with the aid of the microphone capacitor system.
2. Description of the Related Art
A microphone component of the type mentioned at the outset is described in U.S. Pat. No. 6,535,460 B2. The design of this microphone component includes a substrate, having a sound opening, which is spanned by a diaphragm. A perforated counterelement is situated above the diaphragm, at a distance from it, and is connected to the substrate in the edge region of the sound opening. The diaphragm and the counterelement jointly form a microphone capacitor, the diaphragm acting as a movable electrode, while the stationary counterelement is equipped with a rigid counterelectrode.
The circular diaphragm of the known microphone component is tied in to the layer construction of the component via spring elements. In the case of sound pressure, these spring elements are first of all deformed, so that the diaphragm is deflected essentially plane-parallel. In this context, the air leakage current path changes in the area of the spring elements. This flow path increases with increasing diaphragm deflection, which leads to a deterioration of the measuring signal, particularly at high sound levels.
In the case of the known microphone component, the diaphragm and the spring elements are patterned from a thin conductive polycrystalline layer. Such diaphragm patternings, based on their slight thickness and superficial roughness of polycrystalline layers are particularly sensitive to loads that suddenly occur, especially with respect to accelerations such as may occur, for instance, in the case of impacts or falling down.